Offshore quick release-reconnect coupling



Jan. 6, 1970 H. P..BEZNER ETAL OFFSHORE QUICK RELEASE-RECONNBCT COUPLINGFiled March 18, 1968 2 Sheets-Shed 1 INVENTORS. HUBERT P. BEZNER,JEFFERSON C.TAYLOR,JR., CARROLL .WOOLLEY, LMM/ ATTORNEY.

Jan. 6, 1970 H. P. BE ZNER- Em.

OFFSHORE QUICK RELEASE-RECONNECT COUPLING Filed March 18, I968 2Sheets-Sheet 2 INVEN'IORS, HUBERT P. BE ZNER JEFFERSON C. TAYLOR JR.CARROLL A. WOOLLEY ATTORNEY.

US. Cl. 251148 4 Claims ABSTRACT OF THE DISCLOSURE A quickrelease-reconnect coupling for use in drill stem testing from a floatingvessel. One coupling member, connected to the lower end of a pipe stringsuspended from the floating vessel, is lowerable and attachable to astationary coupling member connected to a subsea tubing extending from asubsea wellhead. A sealed connection between the suspended pipe stringand the subsea tubing is effected by lowering, stabbing and latching thecoupling member connected to the pipe string onto the stationarycoupling member. The latched coupling members are released from eachother by applying hydraulic pressure to the coupling member connected tothe pipe string. The pipe string may then be disconnected from thesubsea tubing by raising the suspended pipe string and the couplingmember connected to it. The subsea tubing is preferably provided with ahydraulically operated closure valve which is closed any time there isseparation of the pipe string and tubing and can be hydraulicallyoperated or opened after the pipe string and tubing are connectedtogether. The coupling members are formed with passageways to providefor passage of fluid therethrough to operate the tubing closure valve.

BACKGROUND OF THE INVENTION The present invention generally concernsdrill stem testing from a floating drilling rig or vessel and moreparticularly, coupling apparatus for quickly releasing and reconnectingsubsea equipment to a pipe string which is suspended from the floatingvessel.

Drill stem testing from a floating drilling vessel requires that arapid, safe shutdown technique be available so that a subsea well can behurriedly secured when it is necessary to move off the well locationbecause of equipment failure or bad weather. In addition to rapid, safewell shutdown and rapid disconnection of the suspended pipe string andsubsea equipment, the coupling should be capable of ready reconnectionof the suspended pipe string to the subsea equipment for continuedtesting of the well or termination of the test.

In many drill stem test operations, a fail safe valve is located in thetubing in or slightly below the subsea blowout preventer (BOP) stack.This valve is held open with hydraulic pressure and automatically closeswhen that pressure is released. Accordingly, the coupling should providefor passage of fluid therethrough for operation of the hydraulicallyactuated fail safe valve.

The present invention satisfies all of the aforementioned requirements.A stab-connect, hydraulic-release coupling device is used to rapidlyrelease the pipe string suspended from the floating vessel from thesubsea equipment at a point above a closure valve located in the subseatubing (after releasing opening pressure to allow the closure valve toshut) and reconnect that pipe string to the subsea tubing after theemergency which required shutting in the well and removal of the pipestring is over. The closure valve is again opened after reconnecting thepipe string to the subsea tubing. The hydraulic release feature of theUnited States Patent 3,488,031 Patented Jan. 6, 1970 ICC coupling isimportant because motion from the floating vessel renders stab-connect,rotation-release devices undesirable. Two hydraulic conduits, one tocontrol operation of the connector release coupling and the other tocontrol operation of the closure valve in the subsea tubing, extend fromthe coupling and subsea tubing, respectively, to the floating vessel.

SUMMARY OF THE INVENTION In accordance with the teachings of theinvention, the apparatus comprises, briefly, a first hollow couplingmember attachable to the lower end of a pipe string suspended from afloating vessel and having a sealing surface and latch means providedwith a latch dog; a second hollow coupling member adapted to beconnected to subsea equipment and having a latch recess to be engaged bysaid latch dog and an inner sealing surface adapted to engage saidsealing surface of said first coupling member. The first coupling memberlatches automatically with a positive mechanical locking action whenstabbed onto the second coupling member. Application of hydraulic fluidpressure to said latch means permits said latch dog to retract from saidlatch recess and release of hydraulic fluid pressure from said latchmeans causes said latch dog to lock in said latch recess. A passagewayin said first coupling member communicates with a conduit which extendsto the floating vessel for supplying hydraulic fluid to said latchmeans. Also, other passageways are located in both said first and secondcoupling members to communicate with another conduit which extends tothe floating vessel to supply hydraulic fluid pressure to ahydraulically operated closure valve located in subsea equipmentpositioned below the coupling members. Engageable splines are providedat the ends of the coupling members to prevent rotation of the couplingmembers relative to each other.

The objects and advantages of the invention will be more apparent from amore detailed description of the invention which follows.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a pipe stringsuspended from the water surface coupled to stationary subsea apparatusby means of the release-reconnect coupling of the invention;

FIG. 2 is a vertical view of only the stationary subsea apparatusillustrated in FIG. 1;

FIGS. 3A, 3B are vertical, partly sectional views show ing in greaterdetail the release-reconnect coupling members of the invention as theyare being connected together; and

FIG. 4 is a vertical view of a portion of the coupling members shown inFIG. 3A showing the release-reconnect coupling members when they arecompletely connected together.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2,there is shown stationary subsea apparatus generally designated 10 whichincludes a wellhead 11 arranged on the sea floor 12, a BOP stack 13mounted 0n the wellhead and a riser latch assembly 14 mounted on the BOPstack 13. A tubing 15 is shown suspended in wellhead 11. Riser latchassembly 14 engages and secures the lower end of a riser or conductorpipe 16 which extends to a floating rig or vessel, not shown.

A ball valve assembly 17 such as one shown on p. 3840 of the 1966-67Composite Catalog of Oil Field Equipment is connected into a lowertubing or pipe 18. The BOP stack 13 is provided with rams 19 for closingoff the annulus surrounding assembly 17. Details of the ball valveassembly are not shown; however, a flexible conduit 20, 20' extends tothe earths surface and supplies hydraulic fluid pressure to the ballvalve assembly to maintain tubing 18 open. Release of the hydraulicfluid pressure in conduit 20, 20' causes the ball valve assembly toclose off tubing 18. The upper end of tubing 18 is screw-threadedlyconnected to a tubular coupling member 21 which is provided with a latchrecess 22 at its upper end (see also FIGS. 3A, 3B and 4). Stationarymandrel coupling member 21 is adapted to be latched to a tubularcoupling member 25, the external surface of which is provided withspacer ribs 26 for maintaining coupling member 25 centrally positionedwithin riser 16. Coupling member 25 is screw-threadedly connected at itsupper end to the lower end of a pipe string 28 (see FIG. 3A) whichextends to and is suspended from the floating vessel. A flexible conduit29 is connected at its lower end to the upper end of coupling member 25.This conduit also extends upwardly along pipe string 28 to a source ofhydraulic fluid pressure on the floating vessel.

Referring to FIGS. 3A, 3B and 4 for a more detailed description of theconnection between coupling members 21 and 25, there is shown on theinterior surface of coupling member 21 below latch recess 22 a splinedportion 40 and a passageway 41. The upper end of passageway 41terminates at a port 42 and the lower end thereof terminates at a portconnected to conduit 20 (see FIG. 1). The interior surface 43 ofcoupling member 21 forms a seal with a complementary surface 43' ofcoupling member 25.

Coupling member 25 includes a stinger member 44 having a splined portion45 on its lower exterior surface which is adapted to engage and meshwith the splined portion 40 of coupling member 21. Coupling member 25also contains a passageway 46, the lower end of which terminates in aport 47 which aligns with port 42 in coupling member 21 when thecoupling members are latched together, as illustrated in FIG. 4. Outersealing surface 43' surrounding port 47 sealingly engages surface 43when the coupling members are latched together. Another passageway 48formed in coupling member 25 is attached to conduit 29 at its upper endand terminates at its lower end in a chamber 49 formed in couplingmember 25. A piston 50, latch sleeve 51 and a spring 52 are arranged inchamber 49. Latch sleeve 51 is provided with an inner upper recess 53and an inner lower recess 54. A lug sleeve 55 having an outer recess 56is located in a recessed portion 57 formed in coupling member 25. Aspring 58 is also located in recessed portion 57. A lug 60 is arrangedin a slot located in coupling member 25. Lug 60 is positioned so as toengage recess 53 in latch sleeve 51 and recess 56 in lug sleeve 55. Alatch dog 61 is arranged in another slot located in coupling member 25.Latch dog 61 is positioned so as to engage recess 54 and recess 22 (incoupling member 21).

OPERATION When it is desired to connect pipe string 28 to tubing 18, thelower end of pipe string 28 to which coupling member 25 is attached islowered along with conduits 20' and 29 through riser 16 until the levelof coupling member 21 is reached. As best illustrated in FIGS. 3A, 3Band 4, coupling member 25 is further lowered until stinger 44 slidesinto the upper end of coupling member 21 and splined portions 40 and 45engage and mesh together. A coupling member 25 is lowered into couplingmember 21, the top of coupling member 21 engages the bottom of lugsleeve 55 and forces lug sleeve 55 upwardly against the bias of spring58. Such action positions latch recess 22 adjacent latch dog 61 andpermits lug 60 to move inwardly out of recess 53 of latch sleeve 51. Inthat manner, latch sleeve 51 is permittedto move upwardly under the biasof spring 52 to urge and then retainlatch dog 61 engaged with latchrecess 22. Coupling members 21 and 25 are now releasably latchedtogether. Sealing surfaces 43 and 43' effetltively seal ofi the interiorand exterior of the coupling members and effectively isolate the flowpath through passageways 41 and 46. In this position of the couplingmembers, hydraulic fluid pressure is applied from the floating vesselthrough conduit 20, passageway 46, port 42, conduit 41 and conduit 20 tothe ball valve or closure assembly 17 to actuate the valve and therebymaintain tubing 18 open.

When it is desired to release pipe string 28 from tubing 18, hydraulicpressure is released from the ball valve assembly 17 to permit the valveassembly to close tubing 18 automatically. Then, hydraulic pressure isapplied from the floating vessel through conduit 29 to chamber 49 abovepiston 50 to force latch sleeve 51 downwardly against the bias of spring52 to permit latch dog 61 to retract from engagement with latch recess22 on coupling member 21. Coupling member 25, together with pipe string28, is then raised and removed from riser 16. Lug sleeve 55 moves downunder the bias of spring 58 and urges lug 60 outwardly into recess 53 inlatch sleeve 51. Lug 60 retains latch sleeve 51 in the down or cockedposition.

What is claimed is:

1. Apparatus for use in offshore operations comprising:

a first hollow coupling member adapted to be attached to the lower endof a pipe string suspended from a floating vessel;

a second hollow coupling member adapted to be connected to subseaequipment and to said first coupling member and having a latch recesslocated adjacent the upper end thereof and an inner sealing surface;

said first coupling member having mechanical locking and hydraulicallyreleasable latch means provided with a latch dog adapted to engage andbe locked in said latch recess when said first and second couplingmembers are connected together;

said first coupling member having an outer sealing surface adapted toengage sealingly said sealing surface of said second coupling memberwhen said first and second coupling members are connected together;

a first passageway in said first coupling member and a second passagewayin said second coupling member, said first and second passagewaysforming a sealed off, continuous flow path through said coupling memberswhen said coupling members are connected tog'ether; and

means adapated to supply hydraulic fluid pressure to said latch means topermit said mechanically locked latch dog to retract and disengage fromsaid latch recess.

2. Apparatus as recited in claim 1 including means arranged on the lowerend of said first coupling member and on the upper end of said secondcoupling member adapted, when said coupling members are connectedtogether, to prevent rotation of said coupling members relative to eachother.

3. Apparatus as recited in claim 2 including a hydraulically operatableclosure valve arranged in said subsea equipmentfsaid first passageway insaid first coupling member being adapted to be connected to a source ofhydraulic fluid pressure and said second passageway in said secondcoupling member being adapted to be connected to said hyraulicallyoperated closure valve.

4. Apparatus as recited in claim 3 wherein said latch means includes:

a chamber;

a piston arranged in said chamber adapted to be moved in onelongitudinal direction upon application of hy draulic fluid pressure tosaid chamber when said coupling members are connected together;

a first sleeve member provided with two spaced apart recesses arrangedin said chamber below said piston;

a first spring arranged in said chamber below said 5 6 first sleevemember adapted to bias said first sleeve lug member to move into saidone recess in said member in an opposite longitudinal direction; firstsleeve member and to permit said latch dog a second sleevememberprovided with arecess; to move into said other recess in saidfirst sleeve a second spring adapted to bias said second sleeve memberto permit disconnection of said first and member in said onelongitudinal direction; 5 second coupling members. a lug member adaptedto engage said recesses in said References Cited first and second sleevemembers; said latch dog adapted to engage one of said recesses UNITEDSTATES PATENTS in said first sleeve member whereby when said cou- 2 9499 3 19 0 McGowen et 1 251 143 p g members are engaged and Said latch dogis 10 3,325,190 6/1967 Eckert et a1. 285-18 latched in said latchrecess, said second sleeve mem- 3 333 370 7 19 7 Watkins 285 1g ber ismoved in said opposite longitudinal direction 3 3 5 7 7 Knox 5*1 againstthe bias of said second spring to permit said lug member to move out ofone of said recesses in CARY NELSON Pnmary Examiner said first sleevemember and application of hydrau- 15 WILLIAM R. CLINE, AssistantExaminer lic fluid pressure to said chamber moves said piston U S Q X Rand said first sleeve member in said one direction 285 18 141 316against the bias of said first spring to permit said

